LAN Android Transmission-Control Middleware on multiple Android Terminals in a WLAN Environment with consideration of Round Trip Time Ai HAYAKAWA, Saneyasu YAMAGUCHI, and Masato OGUCHI Ochanomizu University Kogakuin University 1. OS Twitter Facebook Skype LINE
[1] [2] [3] (RTT) 2. Android OS Android OS Google 2012 4 OS 69.7% [4] 1 Android Linux [5] Linux OS Android Runtime Dalvik Dalvik UI Application(Home,Telephone,Web) Application Framework Android Runtime Core Libraries, Dalvik VM Ware Library Linux Kernel 2.6 1 Android 2. 1 Android Android OS 2008 9 23 1.0 5 45.6% Android2.3(Gingerbread) 2012 7 Android4.1(JellyBean) [6] GingerBread JellyBean UI TSO(TCP Segmentation Offload) TSO (NIC) LSI TCP NIC TCP CPU CPU TSO CPU JellyBean Android OS TSO JellyBean TSO [7]
2. 2 Android Android Android Android Android Android Dalvik Android Android 3. 3. 1 [3] Android Android 2 LAN (CWND) (CA-STATE) RTT 2 3. 2 ( 3) [8] TCP TCP Android 3 4. 4. 1 4 Android dummynet Android 1 10 RTT Iperf [9] dummynet 4ms 256ms 1 ping RTT Android GingerBread( GB) JellyBean( JB)
6 (JB) 4 4. 2 1 IEEE802.11g 1 Android Model number Nexus S Firmware version 2.3.4 4.1.1 Baseband version I9023XXKD1 Kernel version 2.6.35.7-hiromi0824, 3.0.31-ai Build number GRJ22, JRO03L server OS Ubuntu 12.04 (64bit) / Linux 3.0.1 CPU Intel(R) Core 2Quad CPU Q8400 Main Memory 7.8GiB 7 4ms (RTT) (GB) 4. 3 5 6 GB JB ( ( ) ( )) 5 GB 6 GB JB JB 8 256ms (RTT) (GB) 5 (GB) (cwnd) ping endto-end RTT ( 7 8 9 10) 7 8 GB 60 RTT ( 4ms 256ms) 9 10 JB 2.1 6 5
JB GB RTT TCP RTT RTT RTT Android OS TCP RTT dummynet 5. 5. 1 RTT RTT Android, 5. 2 16ms Android 10 RTT GB JB 11 12 11 (RTT) (GB) 9 4ms (RTT) (JB) 12 (RTT) (JB) 10 256ms (RTT) (JB)
RTT RTT 6. 6. 1 3.1 13 UDP 13 14 RTT (minrtt) min-rtt RTT RTT/(min-rtt) RTT (ratio-rtt) RTT proc RTT 1 TCP 14 6. 2 [10] = [Mbps] * [sec] = / 1 [1.5Kbyte] / = * 1.5[Kbyte] * 8 / [sec] RTT 2 3 ratio-rtt min-rtt 2 GB JB A : 0 < = min-rtt < 100 B : min-rtt > = 100 2 GB JB A B A B max min max min max min max min 1 21 20 63 62 90 80 555 250 2 16 15 63 62 80 60 400 300 3 11 10 46 45 60 50 300 200 4 9 8 36 35 40 30 200 120 5 7 6 28 27 25 20 65 40 6 5 4 23 22 20 10 55 30 7 4 3 21 20 12 8 39 20 8 3 2 17 16 8 5 28 15 9 2 1 15 14 7 3 24 10 10 2 1 14 13 4 2 17 5
3 RTT GB JB A B A B ratio-rtt max min ratio-rtt max min ratio-rtt max min ratio-rtt max min 1.0 63 62 1.0 63 62 1.0 100 80 1.0 555 300 10.0 61 60 2.0 62 60 10.0 80 60 2.0 300 100 15.0 58 55 3.0 56 53 15.0 60 50 3.0 100 20 20.0 53 50 4.0 48 45 20.0 50 40 4.0 10 5 25.0 48 45 5.0 42 40 25.0 40 30 5.0 8 4 30.0 41 40 6.0 36 34 30.0 30 20 6.0 6 3 35.0 36 35 7.0 26 25 35.0 20 10 7.0 5 3 40.0 31 30 8.0 21 20 40.0 10 5 8.0 4 2 45.0 26 25 9.0 21 20 45.0 4 3 9.0 3 2 50.0 21 20 10.0 11 10 50.0 3 2 10.0 2 1 RTT 7. 7. 1 4 Android 10 GB JB 7. 2 15 16 15 GB 4ms 2 256ms 7 4ms 256ms 5 16 JB 256ms 2 16 (JB) RTT RTT ( 18 19) 17 18 RTT (GB) 15 (GB) 256ms JB 17 19 RTT (JB)
Fairness Index [11] Farness Index 1 F airnessindex : fi = ( k i=i xi)2 k k i=i xi2 (1 < = i < = k)(1) 256ms 20 21 GB JB Fairness Index 1 8.1 Android (JB) 8.2 Android Windows Mac OS PC 8. 1 Android 4 256ms Android 4 6 8 22 23 24 20 (GB) 22 Android 4 21 (JB) GB 5 JB 2 TCP 8. 7 TCP 23 24 Android 6 Android 8
8. 2 Android Windows, Mac OS Android Windows Mac OS PC 25 4 26 Android 3 Windows, Mac OS 25 4 2 Android Model number Nexus S Firmware version 4.1.1 Baseband version I9023XXKD1 Kernel version 3.0.31-ai Build number JRO03L Windows OS Windows 7 Hardware vaio CPU Intel(R) Atom(TM) CPU Z550 2GHz Main Memory 2.0 GB Macintosh OS Mac OS X 10.6.8 Hardware MacBook Air CPU 1.86 GHz Intel Core 2 Duo Main Memory 2GB 1067 MHz DDR3 server OS Ubuntu 12.04 (64bit) / Linux 3.0.1 CPU Intel(R) Core 2Quad CPU Q8400 Main Memory 7.8GiB 256ms Android 3 6 Windows Mac OS 26 27 Android Android 3 6 Android RTT Android Android PC 27 Android 6 Windows, Mac OS Android 9. RTT 2 Android OS RTT RTT
TCP 2 5 Android RTT [10] W.Richard Stevens TCP/IP Vol.1 2000 [11] D.-M. Chiu and R. Jain, Analysis of the increase and decrease algorithms for congestion avoidance in computer networks, Computer Networks and ISDN Systems, vol. 17, pp. 1-14, 1989. KDDI NTT [1]. MBL [ ] 09196072 no.44 pp7-12 2007 5 [2]. EIP [ ] 09196072 no.11 pp1-7 2011 9 [3] :. DEIM2013 E6-4 2013 3. [4] gartner: http://www.gartner.com/it/page.jsp?id=2237315 [5] android:developers:http://developer.android.com [6] http://japanese.engadget.com/ [7] http://source.android.com/source/downloading.html [8] :Android Comsys2010 2010 11. [9] Iperf:http://downloads.sourceforge.net/ project/iperf/iperf/2.0.5